ELIZABETH BLAIR, BYLINE: This is Elizabeth Blair. Let's face it, watching any living creature slip, stumble, get squashed or just thwack its enemy is a blast. In the end, said Charlie Chaplin, everything is a gag. And in animation, sky is the limit. Laws of gravity need not apply.

In "Finding Nemo," a big pelican swoops through a window into a dentist's office, flaps all over the place, knocks over the instrument table.

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BILL HUNTER: (As a dentist) Hold still.

BLAIR: In "Toy Story," the almighty claw in the vending machine descends on the hopeful squeaky toys.

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UNIDENTIFIED GROUP: (As character) The claw.

UNIDENTIFIED MAN #1: (As character) The claw is our master.

UNIDENTIFIED MAN #2: (As character) The claw chooses who will go and who will stay.

TOM HANKS: (As Woody) This is ludicrous.

BLAIR: From "Despicable Me," one minion ping pongs another minion who's hooked to the end of a fishing line.

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BLAIR: In the big studio features, there are hundreds of people who spend their days figuring out how to manufacture this silliness from the ground up. So where do they go for inspiration? Chris Buck, co-director of "Frozen," used to teach animation at Cal Arts. He says he would tell his students, go out into the world and observe.

CHRIS BUCK: Just become a fantastic observer of people, animals, everything.

BLAIR: How they're built, how they bend, how their bodies move when they trip and, above all, how they feel. Dean Deblois, who co-directed "How to Train Your Dragon," says sometimes it takes a team of animators coming together for a gag session.

DEAN DEBLOIS: Where we come up with, like, here's the movie. It's working really well. Are there 10 percent more laughs we could get just by, you know, putting a bunch of smart people together and saying, what if we did this?

BLAIR: Jimmy Hayward, who recently directed "Free Birds," learned a valuable lesson when he was just getting started as an animator. One of his first jobs was on "Toy Story."

JIMMY HAYWARD: These toys were trying to actually kill each other. They're like throwing each other out of windows and off moving trucks, into the jaws of dogs. I remember thinking, like, wow, where there's great conflict and great peril, there's great room for comedy.

BLAIR: There is great peril in the new movie "Frozen." Co-director Jennifer Lee says, for a teaser, they wanted to find a clever way to introduce the oddly adorable snowman Olaf to the goofy looking reindeer, Sven. So they had a gag session.

JENNIFER LEE: We were having these big philosophical conversations about what do a reindeer and a snowman have in common. And the thing we just got to is, well, they both like carrots.

BLAIR: So think about it. Some of the most respected minds in animation figured out not only that they both like carrots, but that just one carrot between them would cause great, dramatic tension. When Olaf the snowman sneezes...

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JOSH GAD: (As Olaf) Achoo.

BLAIR: ...his carrot-nose flies off and lands in the middle of an ice pond.

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BLAIR: The reindeer thinks snack, and the scramble for the carrot is on.

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BLAIR: The animators had a field day with Olaf. The snowman uses one of his twig arms to catapult himself across the ice. When he falls off a cliff, the snowballs that are his body rearrange in mid-air.

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BLAIR: Olaf is voiced by Josh Gad. He says he was in awe of how the animators took full advantage of the fact that Olaf is made of snow.

GAD: What does snow do? It builds on itself. It can melt. There are so many opportunities for this character to add or subtract mass, and I think that that became such a unique part of the comedy in the film.

BLAIR: And this snowman also dreams of experiencing another season.

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GAD: (As Olaf) Oh. I don't know why but I've always loved the idea of summer and sun and all things hot.

GAD: There's a page of different sounds that the human body shouldn't make that they wanted me to do over and over again. And so the animators just kind of sit there and - as you're alone in a booth going ooh, oh, ugh.

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BLAIR: Animators say the best gags are character-driven because what makes them funny is not just the action but the reaction. In "Frozen," the sweet Olaf always looks on the bright side, even when he starts to melt. Elizabeth Blair, NPR News.

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